AGING ABOLISHES CIRCADIAN RHYTHMS OF RORα AND ANTIOXIDANT ENZYMES EXPRESSION IN THE TEMPORAL CORTEX OF FREE RUNNING RATS

DEYURKA NA; NAVIGATORE FONZO LS; CORIA LUCERO, C; LACOSTE MG; ANZULOVICH AC

MERLO, SAN LUIS

Congreso; XXXV REUNION CIENTIFICA ANUAL DE LA SOCIEDAD DE BIOLOGIA DE CUYO; 2017

RORα is a transcription factor that binds RORE motifs in the promoter of clock Bmal1 and other target genes. Antioxidant enzymes contribute to the cellular redox state which is crucial for the molecular clock function. Previously, we showed that antioxidant enzymes activity follow a daily variation in the temporal cortex (TC), which was abolished in aged rats. Herein our objectives were: 1) to investigate endogenous rhythms of catalase (Cat), glutathione peroxidase (Gpx) and Nrf2 genes expression and RORα protein levels in the rat TC, and 2) to evaluate whether aging could affect those temporal patterns. Three- and 22-month-old male Holtzman rats were maintained under constant darkness for 15 days before the experiment, in order to validate the endogenous nature of circadian rhythms. TC samples were isolated every 4 h during a 24h period. RORα protein levels were assessed by inmunoblotting. Cat, Gpx and Nrf2 mRNA levels were determine by RT-PCR. Specific softwares were used to circadian analysis. We observed circadian endogenous rhythms of RORα, Cat and Gpx expression in the TC of young free running rats (Chronos fit, p